Rolling mill



Aug. 28, 1923. M56459 J. M. PERRY ROLLING MILL Filed April 5, 1922 I ammo c $765 J77. jaw/y,

Patented Aug. 19 23.

JAMES ILL PERRY, 0F DETROIII, MICHIGAN, ASSIGNOR TO HIMSELF AND ALBERT B.

' HANSON, OF DETROIT, MICHIGAN.

ROLLING MILL.

Application filed April 3,

To all whom z'tmay concern:

Be it known that 1, JAMES M. PERRY, a citizen of the United States of America, re-

siding at Detroit, in the county of VVayne' and State of 1Michig'an, have invented. certain new and useful Improvements in Rolling Mills, of which the following is a specification, reference being had therein to the "accompanying drawings.

This invention relates to improvements in Rolling Mills, pertaining more particularly to -mills utiliz ng a single pass, the rolls which form the pass being of substantially equal diameter, these rolls being of the contactdrivcn type and each supported by a roll of lar e diameter as compared to the diameter 0% these active rolls, the arrangement producing what may be termed a four-high mill, the rollsof large diameter forming the lower and upper rolls of the set of the rolls, the two active or reducing rolls being the intermediate rolls of the set.

Mills of this type are especially adapted for use in rolling thin plates and especially where the plates are in pack arrangement. lVhere therolls of the pass are of equal and large diameter, the reduction made inthe pass is more or less limited by reason of the comparatively large radius of the are of the rolls which is in contact With the material, 'thus placing a limit to the amount of reduction possible during a single pass of the material and increasing the number of pass-es required to produce the desired gauge of sheet. \Vhere the arrangement employs rolls of difierent diameter as the rolls of the pass, the difference in radius of the two arcs provides for an unequal bite on the metal, so that a greater reduction is had on one side than on the other, a condition which makes such arrangement useless Where the material is being rolled as a pack such an arrangement canand is. usedthe three high typefor rolling single plates but these mills do not attend t to produce the thin gauge sheets in pact form because of this.

ditticulty of. unequal reduction.

A number of problems are presented in connection with mills of the singlepass type where the attempt is made to employ four-high principles. The two-high type is generally employed, but the rolls are of comparatively large diameter with reduction small. In the four-high type the'in- 1922. Serial No. 549,287.'

termediate rolls are of comparatively small under reductions of such high value the pressures applied to the bearings of the rolls are extremely large, and the small diameters of the rolls practically prevent the use of large diameter journals at the ends of these rolls, so that there is constant liability that the shearing strains placed on the journals will quickly damage the rolls and render them unserviceable. And if this is avoided, these pressures on the journals quickly wear the bearings in such manner that the rolls become loose and fwobbly and therefore unserviceable.

Another problem arises because of the single-pass condition and the necessity for repeatedly passing the material through the pass because of the small reduction action required to prevent rendering the rolls unto such an extent as to set up conditions of undue'expansion. This problem has led to the development of the practice of rollturning and heat. expansion, one of the rolls being turned with a concave surface, the opposing roll then being brought to a. complemental relation by making a number of dummy passes of material, the two rolls becoming heated by this action and brought to an approximate uniformity; the difiiculty comes from maintaining uniformity in the heat expansion, as well as the time and labor required in the roll-turning and the heat-expanding activities, a difficulty that is especially onerous Where the mill is of the two-high type.

There is no material difliculty in mounting a set of rolls of the four-high type with the intermediat'e rolls of smaller diameter, and with the axes of the rolls in vertical alineinent-such mounting simply involves tice. But such arrangement is of no material advantage in service, for reasons above indicated, the pressure produced during rollingwhich reach very large valuesbeing opposed only by the bearings and journals to be found in a change in the mounting or rather in the location of the axes of the j several rolls forming the set. I have found. that there is a constant tendency of the contact-driven rolls to move in the direction of movement of the driver for the roll, and by producing the characteristics of a wedge space of decreasing dimensions corresponding to the diameter of the roll ao tive in this direction of tendency, I am able to cause the rolls themselves to set up the conditions of support such as to prevent these high pressures becoming effective on the roll journals, of the active reduction rolls; in other words, the set of rolls then become stable through the fact that increase in pressures such as would tend to increase this tendency -to move with the driver, acts .to attempt to force the roll into a space of less dimensions and thus sets up a resistance value opposing the pressures being exerted, such resistance value not affecting the rotation of the rolls but having a direct effect on the tendency of the roll axes to be shifted inthe direction of driver movement in presence of such pressures.

It is this solution that forms the basis of the present invention and which is embodied in an arrangement by which the axes of the several rolls are so-located with respect to a definite liiie:which may be the line connecting th axes of the upper and lower rolls-as to set up this wedge space characteristic with respect to the two intermediate rolls, these wedge spaces extending in opposite directions in the two rolls, due to the fact that the driver for one intermediate roll moves in a direction opposite the direotion of movement of the driver for the other intermediate roll, the'two drivers referred to being the lower roll and the plate or pac and which I am including under the general term of work respectively.

To these and other ends, therefore, the nature of which will be re 11y understood as the invention is hereinafter disclosed, my invention consists in the improved con-- structions and combinations of parts herematter more particularly described, illustrated int-he accompanying drawings, ancl more particularly pointed out in the appended claims.

In the accompanying drawings, in which naeaaae at a, the lower intermediate roll at b, the

upper intermediate roll at c and the upper roll at 0'. Of these, roll a is the driver, rolls 7), c and d being contact driven. The view shows the rolls 6 and a in contact, this being the position when no work is being reduced;

In this view the axes of rolls a and d are shown as in vertical alinemen't, but this is more or less illustrative. Such alinemen-t is preferred, but, if desired, the axis or roll dimay be shifted to either side of the vertical line 5 which represents such alinement of the axes of the two rolls, .it being understood, of course, that the axes of rolls 1) and 0 will be properly arranged to carry out thefundamcntal features of the invention, when such 0 ange is made.

6 indicates the work and which may be a single plate or a pack of plates, the

conditions of an active arc of compara tiv'ely small radius. It will be understood of course that the entrance of the work will space rollw from roll 6, thus placing work 6 as the driver for rolls 0 and d. the motive power for the set of rolls being applied. only to roll a, the remaining rolls being contact drive-n.

For the purpose of indicating the general fundamentals of the invention a brief explanation will be made of the general action if the two rolls 6 and c were arranged with their axes on line 5, thus placing the axes of the four rolls in vertical alinement. With such arrangement, thev tangent of the line of contact between each'pair of rolls would extend at direct right angles or perpendicular to line 5. If the work were entered in the pass ofsuch arrangement, the pressures set up would be exerted in directions such as to tend to cause the intermediate rolls to shift the axes away from such line, and any shifting tendency would tend to carry the rolls into a space of increasing width and thus render the rolls less active. The only resistance to this action is that provided by the journals and bearings of the active rolls, thus setting up conditions of shearing strains on the journalsif the bearings be capable of resisting the intense effects of wear-or rapid deterioration of the bearings, or both. And this effect will rapidly increase as the amount of reduction per pass increases; so that. a mill of such arrangement would be practically effective only under conditions where the pressures set up by the reducing action are not sufficient to produce these effects on the journals and bearings in other 'words, the percentage of reduction must be retained at a low amount.

One variation from such arrangementand which indicates one embodiment of the present invention-is shown in the location of the axes of rolls 1) and c in Fig. 2. As will be seen, the axis of roll I) is shifted to the right of line 5, line 6 indicating the line connecting the axes of rolls a and 6, pro ducing an angle value between lines 5 and 6. It will be readily understood that With this change, the tangent of the line of contact of rolls a and 7) will extend at right angles or perpendicular to line 6 as indicated by line 6*.

The axis of roll 0 is also shifted to the right of line 5; the length of shift of this axis is not limited, however, to that which would preserve the angle value between lines 5 and (i, but is increased sufliciently to produce a greater angle value between a line 7which connects the axes of rolls 6 and 0- and line 5, the result being that the line 7 --which represents the tangent to the line of contact between rolls 6 and a and extends perpendicular to line 7'is not parallelto line 6 but that lines 6 and 7 converge away from roll 6 toward the rightas indicated by arrow b-thus setting up the characteristic of a wedge space located on that side of line 5 corresponding to the direction of rotation of driver a.

As will be seen, line 8, which connects the axes of rolls 0 and d. also extends at an angle to line 5, but the lines of divergence of the angle 5 8 extend in a general reverse direction from the lines of divergence of the lines of angle 5-6, the result being that line 8- which represents the tangent to the line of contact of rolls 0 and (l and extends perpendicular to line 8also varies from a perpendicular to line 5 and in converging relation to line '7' in the direction of the arrow 0. lines 7 and 8 thus setting up the characteristics of a second wedge space, these wedge spaces being located on opposite sides of a coinfpossite line represented by the lines 6- It will be understood, of course, that the particular angles shown are more or less illustrative, and that the angle 5-7 would slightly change in value when the work is introduced, but the disclosure of Fig. 2 will illustrate a fundamental characteristic of the invention and which is found in the presence of the two wedge spacesone for roll I) and the other for roll 0converging from a generally predetermined line With the convergence of the two spaces being in opposing directions from such line, the convergence of one space being opposite to that of the other space. 1

The results obtained by the mounting will be readily understood. Due to the fact that roll a is the driver for roll I), the latter will tend to move in the direction of movement of its driver roll a-in the direction of arrow b'but since such movement would attempt to crowd roll 6 into a space of less dimension, there is set up a resistance value to offset any effective action on the journals and bearings of roll I) in this direction.. And while line 7 on the opposite side of line 5. would seemingly indicate the presence of an increasing space to'the left of line 5 into which roll I) might tend to move, such tendency is overcome by reason of the fact that roll b to move in this direction, must move upward on roll a in order to reach the high point of the latterrepresented by the intersection of the roll circle and line 5-or mount roll a before roll I) could effectively tend in the direction opposite that indicated by arrow 6'.

The rotation of roll 6 acts to advance the work 6 whenever the latter is introduced into the pass,.the presence of the work in the pass attempting to separate rolls 6 and c, the movement of roll 0 being resisted by roll d held positively by the adjusting mechanism, the latter permitting such vertical movement of rolls 0 and (Z to provide for a pass of the desired dimension. The movement of roll 0 in the vertical direction instead of inthe direction of line 7, slightlyiaffects the value of the angle 5-7 as heretofore pointed out.

Separation of rolls 7) and c transfers the drive of roll 0 from roll 6 to the work 6, the advance of the work causing roll 0 to rotate in the direction shown. As will be understood, the metal of the Work tends to bank up at the entrance to the pass, and it 1s the effect of this that imparts to roll 0 the tendencv to move with its driver (workw) in the direction of arrow 0'. But this movement of roll 0 is resisted by the wedge space characteristic provided by 7* and 8, it being necessary not only that roll 0 advance in a direction to carry it into a space of less dimension, but in addition, the roll would be required to mount roll d indicated by the difference in the perpendiculars of lines' 5 and 8-aswell as tend to mount roll I), it being understood that the strain line of rolls 5 and (2 would extend through the pass to the right of the high-point of roll I).

As a result the tendency of the work to provide 'pressureconditions within the set; of rolls such as a place shearing strains on the journals of rolls 6. and c or produce excessive wear on the bearings of these rolls, is resisted automatically by the presence of these wedge space characteristics, increase in value of pressure application automatically increasing the value of the resistance atiorded by the necessity'oit the rolls 5 and 0 moving into spaces of dimension less than thoseof the rolls themselves.

The invention therefore rests primarily on the discovery by me that the active roll tends to move in the direction of movement of its driver, and that it is possible to build up a wedge space characteristic for such roll through the location of the several roll axes, the wedge space being active in the direction in which the roll would move under such tendency. Because of this the opposing pressures of the active rolls tend to neutralization in the transverse direction, thus relieving the journals and bearings from the strains and wear which would otherwise be set up. Neutralization of pressures in the longitudinal directionthe vertical directionflows from the stability characteristic set up by the arrangement of the rolls; the active rolls are supported by the barrels of rolls a and ol of comparatively large diameter and hence capable of having large journals and bearings.

In the present application of these general principles, l have located the wedge spaces so as to extend in opposite directions,

due to the fact that the drivers for the two,

rolls 7) and c-roll a and work e, respectivelyhave their respective movements in opposite directions, the wedge spaces thus being positioned to resist the roll tendency to move in a direction which would tend to r set up these straining conditions in presence of pressure application. And since the re sistance value builds up concurrently with the building up of the pressure value, the

journal and bearing conditions of the active rolls produce no material limiting factor in determining the maximum reduction possible on the work-during movement through the pass at any time. i

Preferably roll 6 has its bearings arranged to prevent lateral movement of the roll, so* that the angle 5--6 remains practically constant. And I prefer that-the bearings for roll a be similarly arran ,d; however, this is not absolutely essential, and l contemplate an arrangement in which lateral movement is permitted to a limited extent, but such movement is limited so. as to prevent the roll axis reaching a point where the angle 5-7 would be of the same value as the angle 56 or of less value than such angle. And while roll d also might have a lateral movement, I prefer that the bearing for this roll be arranged to be maintained stable against such lateral movement.

neeaesa As before pointed out the axis of roll d need not be vertically alined with that of roll a as long as the general arrangement of the roll axes is preserved. ll prefer, however, the vertical alinement since such arrangement permits of maximum efficiency.

While it have herein shown and described pressed in the accompanying claims, when' broadly construed.

The support, housings, bearings, etc., shown are of any usual and well known character and are not specifically described,

the drawings illustrating one well-known arrangement.

It will be understood, of course, that a succes'sion of mills of this kind may be employed to set up the condititons of a continuous mill; and such arrangement is not only possible but especially advantageous owing to the fact that with the mill of the present invention the rolls can be kept at approximately uniform working temperatures by the application of a cooling agent to the rolls during the period between the reduction activities of the mill on a succession of plates or packs.

Having thus described my invention, what I claim as new is: v

1.. In rolling mill formations of the single pass type, a set of four rolls equal in number on opposite sides of the pass with one of the rolls active as a reducing roll. the reducing roll of a pair being of less diameter than the other roll of the pair, and means for supporting said rolls to locate the axes of the intermediate rolls laterally displaced relative to a line connecting the axes of the two outer rolls, the axis of each intermediate roll being on the same side of the connecting line, the amount of displacement of one of such rolls being greater than that of the other roll.

2. A mill as in claim 1 characterized in that the amount of displacement of the upllllt) per roll is greater than that of the lower necting line of the outer rolls, the converglaterally displaced ing lines setting up a definite angle value of the rolls of a pair relative to the set of rolls, the value of the angle of one pair of rolls difi'ering from that of the other pair of rolls.

4. A mill as in claim 3 characterized in that the value of the angle of the lower pair offirplls is less than that of the upper pair of r0 in the lower roll 5. In a rolling mill of. the four-high type and wherein the single reducing pass d vides the rolls into pairs of rolls on opposite sides of the pass, means for supportin thes rolls to locatethe axes of the interme%iate rolls relative to a line connecting the axes of. the outer rolls of the mill, the axes of the intermediate rolls being located relative to each other in such manner that a line crossing connecting the intermediate roll axes will be inclined relative to" the connecting line of the outer rolls.

6. A. mill ofthe type of claim 5 characthe pass and of one of such spaces opposite in direction to that of the other space.

'11. In a mill adapted to roll sheet packs,

wherein a set of four rolls in four-high arran ment provides the reduction and where= in t e lower roll is the driver with the intermediate rolls forming the passand being contact-driven, means for supporting the rolls in such manner as to locate the axes of the several rolls in position to establish terized in that the axes of the intermediate rolls are located to cause the direction of convergence of the'two lines to be toward the axis of the lower intermediate roll.

7. In a rolling mill of the four-high type,

andwherein the single reducing pass d1- vides the rolls into pairs of rolls on oppo site sides of the pass, means for supporting the rolls to locate the axes of the inter- .mediate rolls laterally displaced relative to a line connecting the'axes of the outer rolls of the mill, the axes of the intermediate rolls being located relative to each other in such manner that a line crossing thepass and connecting the intermediate roll axes will be inclined relative to the connecting line of the outer-rolls and to another line connecting the axes of the two rolls of the lower pair.

8. A mill of the. type of claim 7 characterized in that the line crossing the pass is also angular to a line connecting the axes of the rolls of the upper pair.

9. In a rolling mill of the four-high type wherein the lower. roll is the driver, and wherein the intermediate rolls contact the work during work reduction, means for supporting the rolls in a manner to establish the characteristics of a wedge space for and individual to each of the intermediate rolls and operative to producewedging activity therein when the pass is active in Work reduction, the direction of wedging activity a wedge space characteristic for and individual to each of the intermediate rolls with the direction of increasing wedging activity of such spaces extending in opposite dlrections from a plane extending through the axes of the intermediate rolls, with the wedging space for a roll located on one side alone of such plane.

12. In a rolling mill wherein the reduction rolls of the pass are of substantially equal diameter and form the intermediate rolls of a set with one of the outer rolls active as the driver of the set when the set is inactive and for one of the reduction rolls when the set is active in work reduction, means for supporting the rolls to locate the interme- .diate rolls in wedge spaces for and indi- In testimon whereof I aflix my signaturewitnesses.

J S M. PERRY.

in presence 0 two Witnesses:

Homer G. Snrm,

RLH. :I l: 1' i:- 

